public class Projector implements Device {
    private String brand;
    public Projector(String brand){
        this.brand = brand;
    }
    @Override
    public void powerOn(){
        System.out.println(brand + "投影仪开机,正在预热......");
    }
    @Override
    public void powerOff(){
        System.out.println(brand + "投影仪关机,散热中......");
    }

    @Override
    public void repair() {

    }
}